Tumour markers - Ústav lékařské biochemie 1.LF...
Transcript of Tumour markers - Ústav lékařské biochemie 1.LF...
Tumour markersTumour markers
Marta KalousováInstitute of Clinical Chemistry and Laboratory
Diagnostics,
1st Faculty of Medicine and General University Hospital, Charles University, Prague
Laboratory examination in Laboratory examination in
patients with tumourspatients with tumours
• Blood count
• Basic biochemical parameters – various changes (inflammatory markers, nutrition, metastases – liver, bones – calcium, expansion of tumour - ureter, tumour degradation – uric acid etc.)
• Faecal blood test - screening
• Tumour markers
Tumour markersTumour markers
• Substances determined in the tumour tissue(qualitative) or in serum or other body fluids
(quantitative) of a patient with neoplastic disease
that provide information about biological characteristics of the tumour
• qualitative histopathologic examination –assurance of dg, basis for selection of tumour markers for quantitative determination
• quantitative determination - dynamic changes -progression, regression → prognosis, therapy
Tumour markers Tumour markers -- historyhistory
• 30-ies of the 20th century – chorionic gonadotrophin (physiologically produced by placenta) discovered in young men with testicular tumours (Zondek)
• 70-ies of the 20th century - αααα1-fetoproteindiscovered in liver tumours in mice (hepatomas) (Tatarinov), later on described in human hepatomas(Abelev)
• Further intensive research on further oncofetalantigens and their practical usage in oncology and prenatal diagnostics
• EGTM – European Group on Tumour Markers
Tumour markers Tumour markers ––
clinicalclinical--chemical divisionchemical division
• Oncofetal antigens
• Tissue and organ specific antigens
• Non-specific antigens
OncofetalOncofetal antigensantigens
• Substances produced during the embryonal/fetalperiod or by placenta, postnatally low concentration and increase in connection with some disease, mainly tumours.
Antigens that appear soon in the ontogenesis and postnatally characteristic for less differentiated (i.e. more malignant) tumours.
α1-fetoprotein (AFP)
human chorionic gonadotrophin (hCG)
carcinoembryonic antigen (CEA)
placental alkaline phosphatase (PLAP)
Tissue and organ specific antigensTissue and organ specific antigens
• Physiologically present in healthy tissue or organ, outside released only in minimal amounts
• Pathological states (tumours, inflammation, injury) –increased release
prostatic specific antigen (PSA), neuron specific enolase(NSE), protein S-100, soluble fragments of cytokeratins(TPA, TPS, CYFRA 21-1), CA antigen defined by monoclonal antibodies, squamous cells carcinoma antigen (SCC), thyreoglobulin (TG), hormones and their precursors in tumours from glands which produce them physiologically (e.g. C-peptid in insulinoma)
NonNon--specificspecific antigensantigens
• enzymes and hormones produced by tumours (tumours from organs which do not produce them physiologically – paraneoplastic production), reaction to the presence of tumour
ferritin, lactate dehydrogenase (LDH), thymidinkinase (TK), β2-microglobulin,
some acute phase reactants,
lipid associated sialic acid (LASA)
lung tumours – ACTH, ADH, parathormon etc.
ChemicalChemical characteristicscharacteristics ofof
TU TU markersmarkers
• Enzymes – PSA, NSE,TK, LDH
• Cytokeratines (soluble derivatives) – tissue polypeptide antigen (TPA), fragment of cytokeratine 19 (CYFRA 21-1)
• Hormones (and related substances) – growth hormon, ACTH, TG, PRL, calcitonin, PTH, hCG
• Immunoglobulines (and related substances) – IgG, IgM, IgA, β2-microglobulin, free light chains
• Glycoproteins, glycolipids and saccharides –AFP, hCG, CEA, squamous cell carcinoma antigen (SCC), CA 19-9, CA 125, CA 15-3, CA 549, CA 72-4
•• AFP (AFP (αααααααα11--fetoprotein)fetoprotein) – glycoprotein structurally similar to albumin, physiologically produced by yolk sack, later by fetal liver. Used for dg and monitoring of hepatocellular carcinoma and germ cells testicular and ovarian. Used in prenatal screening of Down syndrome in the 2nd trimester of pregnancy.
•• CEACEA – glycoproteins with 45-60 % of saccharides, MW 180 kDa, present in fetal intestine, used for monitoring of colorectal CA, event. other CA (breast, lung), higher levels in smokers.
•• Human chorionic Human chorionic gonadotrophingonadotrophin ((hCGhCG)) –glycoprotein, α and β subunits non-covalently bound, αsubunit nearly identical with LH, FSH and TSH. Indication of examination: dg of pregnancy, prenatal screening of Down syndrome, monitoring and prognosis of germ cell tumours, trophoblastic disease
•• CA 125CA 125 – monitoring of ovarian CA
•• CA 15CA 15--33 – monitoring of breast CA
•• CA 72CA 72--44 – monitoring of gastric CA
•• CA 19CA 19--99 – glycolipid, determinant of blood group Lewis a (5% of population does not produce it), for monitoring of pancreas CA (and bile ducts)
•• CYFRA 21CYFRA 21--11 – soluble fragment of cytokeratine 19, for lung CA (non-small cell) and urinary bladder
•• NSENSE – for monitoring of small cell lung cancer, neuroblastoma, apudoma, CAVE – hemolysis
•• PSAPSA – serin protease, glycoprotein, monitoring of prostataCA
ratio fPSA/PSA
•• SCCSCC – squamous cell carcinoma antigen, monitoring of head and neck tumours, some gynecological tumours, genital tumours and oesophagus tumour
•• TPATPA – tissue polypeptide antigen, mixture of soluble cytokeratines 8, 18 and 19, monitoring of CA of urinary bladder
•• TPSTPS – tissue polypeptide specific antigen, soluble fragment of cytokeratine 18, monitoring of metastasingbreast CA
•• TKTK – thymidinkinase, marker of proliferation, leukemias
•• ββββββββ22--microglobulinmicroglobulin – hematological malignancies (NHL), influenced by renal function
•• FerritinFerritin – hematological malignancies
•• ParaproteinParaprotein, free light chains , free light chains – monoclonal gamapathy
•• S100BS100B – malignant melanoma
•• ChromograninChromogranin AA – neuroendocrine tumours
•• IsoenzymeIsoenzyme of of pyruvatepyruvate kinasekinase – kidney cancer
•• ILIL--66 – hepatocellular cancer, up to 50 fold increase in extrahepatal metastases
•• MesomarkMesomark – mesothelioma
•• EstrogenEstrogen receptorsreceptors – prediction of the effect of hormonal therapy in breast cancer, determination in the tumour tissue
•• ProgesteronProgesteron receptorreceptor – prediction of the effect of hormonal therapy in breast cancer, determination in the tumour tissue
Determination of tumour markersDetermination of tumour markers
• Immunochemistry
- radio immune assay – RIA, IRMA
- enzyme immune assay - ELISA, EIA, MEIA
- fluorescence assay - FPIA, TRACE
- chemiluminiscence assay - CLIA
• Use the same diagnostic kit from the same
company!!!
Ideal markerIdeal marker
• High specificity – not present in other diseases -non-tumours and in healthy subjects
• High sensitivity – detectable at the beginning of the disease
• Optimal positive and negative predictive value
• Organ specific
• Correlation with the tumour mass and prognosis
does not exist…
Rational usage of tumour markersRational usage of tumour markers
• Not for diagnostics but for monitoring.
They can help in the diagnostic process.
• Positive finding of tumour markers is of diagnostic value, negative finding does not exclude a tumour!!!
For diagnosis, histopathological examination and additional TU markers determination is decisive.
Transient elevation of a tumour marker – inflammation, non-malignant tumour, trauma, after efficient therapy, in decreased renal function – markers which are excreted by the kidneys (CEA)
• Screening - ?
Rational usage of tumour markersRational usage of tumour markers
• Dynamics of changes (increase, although in reference range may indicate a recidive sooner than visualization by CT, US, PET)
TU marker may detect a tumour of 1 mg (106 malignant cells), clinical diagnosis is possible for 109 malignant cells
• Systematic examination – repeated determination after operation, at the beginning shorter intervals, later cca 3-6 months)
• Follow up of more tumour markers – higher probability of detection a tumour
EvaluationEvaluation ofof TU TU markersmarkers
• Ideal situation • reality
healthy healthypatients patients
„cut off“
FN FPfalsenegative
falsepositive
Evaluation of TU markersEvaluation of TU markers
• Specificity = SN / (SN + FP)
probability that a negative test means negative dg
• Sensitivity = SP / (SP + FN)
probability that a positive test means a positive dg
• Positive predictive value = SP / (SP + FP)
• Negative predictive value = SN / (SN + FN)
SP – number of true positive examinations
SN – number of true negative examinations
FP – number of false positive examinations
FN – number of false negative examinations
Evaluation of TU markers Evaluation of TU markers
using ROC curvesusing ROC curves(ROC = receiver operating characteristic)
sensitivity (%)
100 %
0 %100 % 0 % specificity (%)
suitable
TU marker
no
discrimination
among healthy
subjects and
patients
Example
CEA for colorectal CA
• 95% specificity – i.e. 5% of healthy subjects are
falsly regarded as patients with tumours
• 70% sensitivity – i.e. does not detect 30% of
patients with tumours
Interpretation of results ofInterpretation of results of
TU markersTU markers
• In the past – comparison with reference
range (might be suitable for a unique determination of
unknown patient)
• Today recommended determination of
individual baseline values (concentration
of a TU marker in „stabilized“ status, i.e.
after operation – extraction of the tumour
mass) and systematic dynamic follow up
Dynamic follow upDynamic follow upconcentration
of TU marker
in blood
time of follow up
„cut off“
Dynamic follow upDynamic follow upconcentration
of TU marker
in blood
time of follow up
„cut off“
Molecular biology Molecular biology
in diagnostics of tumoursin diagnostics of tumours
• Tumours – mutations of genes which
products regulate cell proliferation,
development, differentiation and cell death
• Oncogenes and antioncogenes
OncogenesOncogenes and their significance and their significance
in tumour in tumour -- examplesexamples
• abl→ tyrosin-protein kinase (leukemias)
• erb B1, B2→ receptors for epidermal growth factor
• c-myc – transcription factor (lymphomas)
• neu(erbB-2)→ receptor for epidermal growth factor (breast CA)
• NF1 – nuclear factor
• ras→ GTP-ase activating protein
AntioncogenesAntioncogenes and their and their
significance in tumour significance in tumour -- examplesexamples
• BRCA 1 and BRCA 2 – reparation of DNA
defects (breast and ovarian CA)
• p53 – regulation of the cell cycle
• RB1 a RB2 – regulation of the cell cycle
(retinoblastoma)
Potential new tumour markersPotential new tumour markers
Proteins and oncoproteins – products of mutated
genes which play a role in cell life, their division,
differentiation and metastasing
ØRegulation of the cell cycle - cyclins
ØApoptosis – Bcl-2 protein, sFas, protein-product of mutated gene p53
ØSignal transduction - c-erbB-2 (Her-2/neu), EGRF, IGF, TNF-α
ØAdhesion - ICAM-1, VCAM-1
ØAngiogenesis – inhibitors of angiogenesis - angiostatin, angiogenin, trombospondin
ØMarkers associated with specific characteristics of tumour cells – matrix metalloproteinases, urokinaseplasminogen activator (uPA) and its inhibitor (PAI-1)
New and potential New and potential
tumour markerstumour markers
• free DNA in plasma (and microsatelite changes)
• free mRNA in plasma
• enzymes of DNA synthesis in tissue samples
• mammaglobin - breast cancer
• heparanase
• …
LiteratureLiterature
• Zima T. : Laboratory diagnostics. 2nd Edition. Galén Karolinum Praha 2007, 906 p. in Czech
• Kalousová M. et al.: Pathobiochemistry in schemas. Praha Grada Publishing 2005, 264 p. in Czech